Selective vagal innervation principles of ganglionated plexi: step-by-step cardioneuroablation in a patient with vasovagal syncope.

Cardioneuroablation (CNA) is an endocardial ablation technique aiming to prevent the autonomic imbalance occurring in vasovagal syncope (VVS). A 46-year-old female was referred to our center for pacemaker implantation due to recurrent syncopal episodes despite conventional treatments. A 22-s asystole was detected on head-up tilt testing. After a discussion with the patient and her family, we decided to perform CNA. Positive response was confirmed, and procedural endpoints were defined using pre-procedural atropine response test. Ganglionated plexus (GP) sites were detected and ablated by using fractionated electrogram (FE)-based strategy. During baseline electrophysiological study, AA and PR intervals were calculated as 810 ms and 164 ms, respectively. Based on our ablation order, radiofrequency ablation (RFA) was started from the left inferior and left superior GPs, respectively. A significant vagal response with sinus pauses and atrioventricular (AV) block was detected during RFA. Ablation of the right superior GP caused a significant increase of sinus rate with continuing AV block. After completion of ablation on the right superior and inferior GPs, PR interval was still 164 ms although AA interval decreased to 640 ms. After RFA on the posteromedial left GP which provides mainly vagal innervation of AV node, PR interval and cycle length of sinus node were detected as 134 ms and 540 ms, respectively. Selective parasympathetic innervation principles of the sinus node and AV node were previously demonstrated. We described a case of successful parasympathetic denervation of the sinus node and AV nodes using CNA.